1. Field of the Invention
The present invention relates to a sheet feeding apparatus for automatically feeding sheets one by one.
2. Related Background Art
Recording systems such as printers, copying machines, facsimiles and the like are so designed that an image comprised of a dot pattern is formed on a recording sheet such as a paper sheet, plastic film and the like by energizing an energy generating means of a recording head in response to inputted image information.
Such recording systems can be grouped into an ink jet recording system, a wire dot recording system, a thermal recording system, an electrophotographic recording system or the like in accordance with recording types. Further, a recording sheet used with the recording system may be a thicker sheet such as a post card, an envelope and the like, a special sheet such as a plastic film or the like, as well as a plain paper sheet. The sheets may be manually inserted one by one or may be automatically and continuously supplied by a sheet feeding apparatus.
FIG. 11 is a perspective view of a conventional recording system B incorporating a sheet feeding apparatus A therein, and FIG. 12 is a perspective view showing a construction of the sheet feeding apparatus A. As shown in FIGS. 11 and 12, the sheet feeding apparatus A generally comprises a sheet supply drive portion constituted by left (L) and right (R) sheet supply rollers 101, 102, a sheet supply roller shaft 106, a drive gear 107 and the like, and a sheet supply cassette portion constituted by left (L) and right (R) side guides 103, 104, a pressure plate 105 and the like and stacking sheets therein. The sheet feeding apparatus is so designed that the sheets are separated and supplied one by one via left (L) and right (R) separating claws 109, 110 by driving the sheet supply rollers 101, 102 by transmitting a driving force from the recording system B to the drive gear 107.
However, in the above-mentioned conventional case, since the sheets were separated by the left and right separating claws, the following drawbacks arose.
(1) To cope with various widths of plural kinds of sheets, since not only the guides but also the separating claws and the sheet supply rollers must be slid bodily on the sheet supply roller shaft, the number of parts is increased, and the apparatus itself is made expensive.
(2) Since the number of parts is increased, it is difficult to save the space effectively, thus making the compactness of the apparatus difficult.
(3) Since the number of parts is increased and the construction becomes complex, is hard to ensure the reliability.